This was the signal.

The assassins sprang from their retreat and darted upon Selim, who fell, exclaiming, like Caesar, "And it is thou, my son, who takest my life!" At the sound of the tumult which followed the assassination, Selim's bodyguard, running up, found Ali erect, covered with blood, surrounded by assassins, holding in his hand the firman displayed, and crying with a menacing voice, "I have killed the traitor Selim by the order of our glorious sultan; here is his imperial command." At these words, and the sight of the fatal diploma, all prostrated themselves terror-stricken.
Ali, after ordering the decapitation of Selim, whose head he seized as a trophy, ordered the cadi, the beys, and the Greek archons to meet at the palace to prepare the official account of the execution of the sentence.
They assembled, trembling; the sacred hymn of the Fatahat was sung, and the murder declared legal, in the name of the merciful and compassionate God, Lord of the world.
When they had sealed up the effects of the victim, the murderer left the palace, taking with him, as a hostage, Mustapha, son of Selim, destined to be even more unfortunate than his father.
A few days afterwards, the Divan awarded to Ali Tepeleni, as a reward for his zeal for the State and religion, the sanjak of Thessaly, with the title of Dervendgi-pacha, or Provost Marshal of the roads.

This latter dignity was conferred on the condition of his levying a body of four thousand men to clear the valley of the Peneus of a multitude of Christian chiefs who exercised more power than the officers of the Grand Seigneur.

The new pacha took advantage of this to enlist a numerous body of Albanians ready for any enterprise, and completely devoted to him.
With two important commands, and with this strong force at his back, he repaired to Trikala, the seat of his government, where he speedily acquired great influence.
His first act of authority was to exterminate the bands of Armatolis, or Christian militia, which infested the plain.

He laid violent hands on all whom he caught, and drove the rest back into their mountains, splitting them up into small bands whom he could deal with at his pleasure.